Webbing adjusters have been used in mountaineering, motorcycle and bicycle helmets, and other applications that benefit from orderly, adjustable strap arrangements and/or secure connections. Many different strap arrangements, buckles and adjusters are employed in different types of helmets.
Bicycle helmets in particular often have strap arrangements that are inconvenient or difficult to adjust. Bicycle helmet strap arrangements commonly involve two straps on each side of the helmet. The straps on each side are typically mounted to anchor points at the front and rear of the helmet, fed together through a webbing adjuster and attached to a buckle. The two straps are brought together through the buckle for added security and strength.
One function of a webbing adjuster is to adjust the fore and aft position of the straps so that the helmet sits properly on different wearer's heads. Since, in a conventional arrangement, separate straps are attached to different points on the helmet and fed through a single adjuster, the portions of the straps between the helmet anchor points and the adjustor can become twisted. Twisted straps can make the helmet difficult to adjust and may lead to undesirable effects such as additional aerodynamic drag, wind noise, and/or jammed adjusters. Conventional webbing adjusters are also frequently difficult to adjust because the separate fore and aft straps are cinched together to form the chin strap, thus terminating in a buckle.
Another challenge in the design of bicycle helmets is consideration of various safety standards such as European Standard EN 1078:201 or the CPSC Safety Standard For Bicycle Helmets (16 CFR Part 1203) in the United States. Among other things, these standards set requirements for design and testing of qualifying products, and thus may limit design choices available to persons of ordinary skill in the design of helmets and helmet retention systems.